Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ELECTRONIC ARTICLE SURVEILLANCE DEACTIVATOR USING
VISUAL PATTERN RECOGNITION SYSTEM FOR TRIGGERING
FIELD OF THE INVENTION
The present invention relates generally to a method and system for
deactivating
Electronic Article Surveillance ("EAS") tags and more specifically to a method
and system
for deactivating EAS tags using a visual pattern recognition system for
triggering.
BACKGROUND OF THE INVENTION
Recent advances in automatic article identification technology provide retail
and
wholesale sales facilities with an improved means for detecting when an
article is being
shoplifted. One such method, Electronic Article Surveillance ("EAS"),
typically includes an
EAS detector and EAS devices commonly called labels, tags, markers or
transponders. The
EAS detector transmits a radio-frequency ("RF") carrier signal to any EAS
device within a
certain range of the detector. An active EAS device responds to the carrier
signal by
generating a response signal of a predetermined frequency, which triggers an
alarm when
received at the detector. For example, an active magneto-acoustic EAS tag
resonates at a
predetermined frequency when stimulated by an interrogation signal. When a
customer
purchases an item that is protected by an active EAS tag, a cashier typically
deactivates the '
tag using a deactivator that produces a magnetic deactivation field that
alters the resonant
frequency characteristic of the tag so that it no longer resonates at the
predetermined
frequency. The item may then be removed from the store without triggering an
alarm.
Current EAS deactivation systems require an enabling signal to trigger the
deactivation sequence. Presently, the primary method used to trigger the
deactivation
sequence involves the use of an interrogation field. The interrogation field
is typically a
radio-frequency magnetic field used to detect the presence of an EAS tag. When
an EAS tag
enters the interrogation field, the magnetic field induces a frequency
response signal, or
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"EAS marker signal," for circuitry located within the EAS tag. Frequency
detectors detect
response signals having a resonant frequency within a predetermined range.
When the
amplitude of the EAS tag response signal is greater than a predetermined
threshold, the EAS
deactivation sequence is triggered.
In addition to detecting the mere presence of the EAS tag, the deactivator
must also
know the orientation of the EAS tag in order to assure proper deactivation. In
some
deactivators, up to three different magnetic fields are employed in the
interrogation zone.
Each magnetic field is oriented orthogonally to the other fields in order to
ensure that the
EAS tag signal is detected and to determine its orientation. Additional
circuitry may compare
the amplitude of the EAS signal detected in response to each field to
determine which field is
strongest. The coil producing the strongest response is "fired" to deactivate
the EAS tag.
The use of an interrogation field to detect EAS tags has several problems.
Because
the EAS response signal can vary significantly from label to label, it is
difficult to determine
exactly what the predetermined threshold for triggering the EAS deactivation
sequence
should be. This variance can cause the deactivation sequence to be triggered
when the tag is
not in the correct location, thereby causing failures to deactivate ("FTDs").
Additionally, creating and detecting the magnetic field inside the
interrogation area is
very expensive, as at least one receiver and one magnetic field generator are
required per
deactivator. Also, certain materials may not be suitable for constructing
antennas that operate
at high frequencies, e.g., laminated, silicon steel does not operate well
above about 1 or 2
kHz, requiring the use of more expensive materials for the antenna
composition. Thus, the
EAS tag detection circuitry alone can potentially add up to about 25% of the
total cost of the
deactivator.
Also, the EAS marker signal provides little certainty as to the orientation of
the EAS
tag. All that is really known is which coil produces the strongest response.
This inaccuracy
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further contributes to additional problems with FTDs. Therefore, what is
needed is a system,
method and EAS tag deactivator for detecting EAS tags without the use of a
traditional
interrogation field.
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SUMMARY OF THE INVENTION
The present invention advantageously provides a method and system for
detecting the
presence of an electronic article surveillance tag with a deactivation zone
without requiring
the use of a traditional magnetic field detector. Generally, the present
invention uses pattern
recognition techniques to detect the presence of an item in the deactivation
zone of an EAS
deactivator prior to deactivating the item's EAS tag.
In accordance with one aspect of the present invention, a method is provided
for
detecting the presence of an electronic article surveillance tag within a
deactivation zone.
Video of an item within the deactivation zone is captured. The video is
evaluated using a
pattern recognition technique to determine the presence of an electronic
article surveillance
tag within the deactivation zone. The electronic article surveillance tag is
deactivated.
In accordance with another aspect of the present invention, an electronic
article
surveillance tag deactivator includes a deactivation zone, a video sensor, a
video pattern
recognition system, and a system controller. The video sensor operates to
capture video of an
item within the deactivation zone. The video pattern recognition system is
communicatively
coupled to the video sensor. The video pattern recognition system operates to
evaluate the
video using a pattern recognition technique to determine the presence of an
electronic article
surveillance tag within the deactivation zone. The system controller is
communicatively
coupled to the video pattern recognition system. The system controller
operates to trigger
deactivation of the electronic article surveillance tag in response to
determining that the
electronic article surveillance tag is within the deactivation zone.
In accordance with yet another aspect of the present invention, an electronic
article
surveillance deactivation system includes an electronic article surveillance
tag deactivator
having a deactivation zone, a video sensor, a video pattern recognition
system, a system
controller, and a deactivation trigger. The video sensor operates to capture
video of an item
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within the deactivation zone. The video pattern recognition system is
communicatively
coupled to the video sensor. The video pattern recognition system operates to
use a pattern
recognition technique to determine the presence of an electronic article
surveillance tag
within the deactivation zone. The system controller is communicatively coupled
to the video
pattern recognition system. The system controller operates to trigger
deactivation of the
electronic article surveillance tag in response to determining that the
electronic article
surveillance tag is within the deactivation zone. The deactivation trigger is
communicatively
coupled to the system controller. The deactivation trigger operates to
deactivate the
electronic article surveillance tag.
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BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention, and the attendant
advantages
and features thereof, will be more readily understood by reference to the
following detailed
description when considered in conjunction with the accompanying drawings
wherein:
FIG. 1 is a block diagram of an exemplary electronic article surveillance
deactivation
system constructed in accordance with the principles of the present invention;
FIG. 2 is a flow chart of an exemplary electronic article surveillance
detection and
deactivation process according to the principles of the present invention;
FIG. 3 is a diagram of an exemplary EAS tag location and bar code package
marking
in accordance with the principles of the present invention;
FIG. 4 is a diagram of an exemplary EAS tag location and package marking in
accordance with the principles of the present invention; and
FIG. 5 is a diagram of an exemplary EAS tag location and package orientation
marking in accordance with the principles of the present invention.
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DETAILED DESCRIPTION OF THE INVENTION
Before describing in detail exemplary embodiments that are in accordance with
the
present invention, it is noted that the embodiments reside primarily in
combinations of
apparatus components and processing steps related to implementing a system and
method for
triggering Electronic Article Surveillance ("EAS") tag deactivation using
visual pattern
recognition. Accordingly, the system and method components have been
represented where
appropriate by conventional symbols in the drawings, showing only those
specific details that
are pertinent to understanding the embodiments of the present invention so as
not to obscure
the disclosure with details that will be readily apparent to those of ordinary
skill in the art
having the benefit of the description herein.
As used herein, relational terms, such as "first" and "second," "top" and
"bottom,"
and the like, may be used solely to distinguish one entity or element from
another entity or
element without necessarily requiring or implying any physical or logical
relationship or
order between such entities or elements. Additionally, the terms "EAS tag,"
"EAS label,"
"EAS marker" and "EAS transponder" are used interchangeably herein.
One embodiment of the present invention advantageously provides a method and
system for detecting and verifying the presence of an EAS tag or EAS marker
using visual
pattern recognition. Detection may be based on recognition of the shape or
markings on the
EAS marker or based on the presence of a bar code or other unique marking that
is on the
packaging near the EAS marker. The location and distance of the marker may be
measured
using stereo or focus based methods to verify that the marker is within the
deactivation zone.
This detection triggers the deactivation sequence.
In another embodiment of the invention, the visual detection system may be
used to
determine the orientation of the EAS marker. This orientation information can
be used by the
deactivator to determine the optimal timing and orientation of the
deactivation field.
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In yet another embodiment of the invention, the video pattern recognition
system may
be used in conjunction with a traditional EAS marker detection system to
provide an
improved system that uses both the EAS label amplitude information and the
visual marker
position, orientation and velocity information to optimally time the
triggering of the
deactivation sequence and the orientation of the deactivation field.
Referring now to the drawing figures in which like reference designators refer
to like
elements, there is shown in FIG. 1, an exemplary electronic article
surveillance ("EAS") tag
deactivation system 10 for detecting and deactivating EAS tags, constructed in
accordance
with the principles of the present invention. System 10 may include a system
controller 12
communicatively coupled to a video pattern recognition system 14 and a
deactivation trigger
16. The video pattern recognition system 14 receives video information from a
video sensor
18 that captures video information of items within a deactivation zone. When
the video
pattern recognition system 14 determines that an EAS tag is within the
deactivation zone,
relevant information is sent to a parameter estimator 20 to calculate
applicable parameters of
the EAS tag. For example, parameters may include the EAS tag or other marker
position,
orientation, and velocity. Note that the parameter estimator 20 may be a stand-
alone device
or embedded within the video pattern recognition system 14 as an integrated
function.
A detection indicator and associated parameters are sent to the system
controller 12
which instructs the deactivation trigger 16 to send a deactivation signal to
the EAS tag
through the use of a deactivation antenna 22. The parameters are used to
determine the
timing of the deactivation sequence and the orientation of the deactivation
antenna 22 when
producing a deactivation field.
Additionally, the deactivation system 10 may optionally employ a traditional
EAS
marker detector 24, e.g., a magnetic field interrogation zone, in combination
with the video
=25 pattern recognition system 14 to more accurately determine the presence
and actual
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orientation of the EAS tag, thereby reducing the number of failures to
deactivate. The
deactivation system 10 may also include an optional ultraviolet ("UV") light
source 26 to
expose ultraviolet markings.
Referring now to FIG. 2, an exemplary operational flowchart is provided that
describes steps performed by an EAS tag deactivator 12 for detecting and
deactivating an
EAS tag within a deactivation zone, in accordance with the principles of the
present
invention. A video sensor 18 captures video information within the
deactivation zone (step
S102). A video pattern recognition system 14 uses known pattern recognition
techniques to
determine the presence of an EAS tag within the deactivation zone (step S104),
e.g., the
video pattern recognition system 14 may be programmed to recognize the shape
of an EAS
tag.
FIGS. 3-5 illustrate exemplary markers and marker placement in accordance with
the
principles of the present invention. As shown in FIG. 3, the video pattern
recognition system
14 may alternatively determine the presence of an EAS tag 28 by detecting the
presence of a
barcode 30, as common practice within the retail industry is to place EAS tags
or labels near
the Universal Product Code ("UPC") barcode 30. The orientation of the bar code
can be used
to establish the orientation of the EAS tag 28 in the case where the EAS tag
28 is located
inside the packaging. Implementation of the present invention may dictate that
all EAS tags
or labels 28 be placed in a designated location near the barcode 30. As shown
in FIG. 4, it is
also contemplated that a unique package marking 32 may be applied during
source tagging to
more precisely define the location and orientation of the EAS label 28 and
source tagging
applications. For example, as shown in FIG. 5, an arrow 34 or other marking
used to denote
orientation may be applied to product packaging at the location of the EAS tag
or label. The
marking may be on the outside of the packaging, directly above, or a pre-
determined distance
from an EAS label attached to the inside of the packaging. Additional
embodiments may
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include the use of ultraviolet ("UV") ink to create the marking. The UV ink is
not visible to
the human eye and requires UV light to be detected by the video pattern
recognition system
14. In this case, the deactivation system 10 may also include a UV light
source to illuminate
the ink and allow detection.
Referring again to FIG. 2, as long as the video pattern recognition system 14
does not
detect an EAS tag (step S106), the video sensor 18 continues to capture video
information
(step S102). If the video pattern recognition system 14 detects an EAS tag
(step S106),
information determined by a parameter estimator 20, such as location,
orientation, and/or
velocity of the EAS tag is used to determine the orientation of the
deactivation field and the
timing for firing the deactivation sequence (step S108). The EAS tag is
deactivated using the
information determined by the parameter estimator 20 (step 5110).
Embodiments of the present invention include several advantages. For example,
the
cost of video sensors is quite low due to their use in low-cost optical
applications such as
webcams, cell phones etc. Also, the cost of video digital signal processing
("DSP") chip sets
used for video pattern recognition applications has dramatically decreased in
recent years.
This creates an opportunity for a significantly lower cost deactivation
triggering technique.
Additionally, the use of video pattern recognition allows for more precise
control over
the timing of the deactivation triggering sequence and orientation of the
deactivation field
resulting in far less failures to deactivate and decreasing the number of
"false alarms" for the
EAS system when legitimate customers exit stores with purchased items that
have not been
properly deactivated. This approach may also dramatically improve the
deactivation range
by providing better control over the timing of the deactivation triggering and
orientation of
the deactivation field. The combination of traditional EAS detection
technology and video
based pattern recognition detection provides a dramatically improved ability
to determine the
optimal timing of the deactivation triggering and the orientation of the
deactivation field.
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Furthermore, embodiments of the present invention save energy as the
deactivation
system either does not produce the magnetic interrogation field at all, or is
able to produce a -
significantly smaller field due to the added detection capabilities of the
video pattern
recognition system. Therefore, the size of components, such as energy storage
capacitors
and power supplies, needed for the deactivation circuit is significantly
reduced.
The present invention can be realized in hardware, software, or a combination
of
hardware and software. Any kind of computing system, or other apparatus
adapted for
carrying out the methods described herein, is suited to perform the functions
described
herein.
A typical combination of hardware and software could be a specialized or
general
purpose computer system having one or more processing elements and a computer
program
stored on a storage medium that, when loaded and executed, controls the
computer system
such that it carries out the methods described herein. The present invention
can also be
embedded in a computer program product, which comprises all the features
enabling the
implementation of the methods described herein, and which, when loaded in a
computing
system is able to carry out these methods. Storage medium refers to any
volatile or non-
volatile storage device.
Computer program or application in the present context means any expression,
in any
language, code or notation, of a set of instructions intended to cause a
system having an
information processing capability to perform a particular function either
directly or after
either or both of the following a) conversion to another language, code or
notation; b)
reproduction in a different material form.
In addition, unless mention was made above to the contrary, it should be noted
that all
of the accompanying drawings are not to scale. Significantly, this invention
can be embodied
in other specific forms without departing from the essential attributes
thereof, and
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accordingly, reference should be had to the following claims, rather than to
the foregoing
specification, as indicating the scope of the invention.
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